JP2022131422A - Liquid discharge head - Google Patents

Abstract

To provide a liquid discharge head which can inhibit flow of a contact material protruding from a joint surface.SOLUTION: A liquid discharge head 4 has: a first substrate including a structure; and a second substrate joined to the first substrate through an adhesive 40. The first substrate is formed with: a joint surface 24 joined to the second substrate through the adhesive 40; and a non-joint surface 29 which is not joined to the second substrate. A recessed part 32 is formed at an area, which is located between a joint end part 25, i.e. a structure side end part of the joint surface 24, and the structure, of an area of the non-joint surface 29.SELECTED DRAWING: Figure 2

Description

The present invention relates to liquid ejection heads.

2. Description of the Related Art A printing apparatus that performs printing by ejecting liquid is equipped with a liquid ejection head that ejects liquid from an ejection port. When a liquid ejection head is formed by bonding a plurality of substrates with an adhesive, excess adhesive protrudes from the bonding surface, which may result in a decrease in yield and deterioration in device characteristics.

Therefore, in Patent Document 1, a method is presented in which a groove (recess) is formed in the bonding surface to which the adhesive is applied, and the surplus adhesive that is generated when the substrates are pressed against each other during bonding can be accommodated in the recess. there is By accommodating the excess adhesive in the recess, it is possible to suppress the adhesive from protruding from the joint surface.

JP 2011-207072 A

However, in Patent Document 1, when the adhesive overflows from the joint surface because it cannot be accommodated in the recess, the recess is formed only on the joint surface, so that subsequent flow of the adhesive can be suppressed. can't As a result, there is a risk that the protruding adhesive will adhere to structures such as the pressure generating element, thereby affecting the recording quality.

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid ejection head capable of suppressing the flow of a contact material protruding from a joint surface.

In order to solve the above problems, the present invention provides a liquid ejection head having a first substrate having a structure and a second substrate bonded to the first substrate via an adhesive, The first substrate is formed with a bonding surface that is bonded to the second substrate via the adhesive and a non-bonding surface that is not bonded to the second substrate. A concave portion is formed in a region of the joint surface between the joint end portion, which is the end portion of the joint surface on the side of the structure, and the structure.

According to the present invention, it is possible to provide a liquid ejection head capable of suppressing the flow of the contact material protruding from the joint surface.

Schematic diagram of a liquid ejection head. The figure which shows the process at the time of joining each board|substrate. The figure which shows the process at the time of joining each board|substrate. Schematic which shows the recessed part of 2nd Embodiment. Schematic which shows the recessed part of 3rd Embodiment. Schematic which shows the recessed part of 3rd Embodiment. Schematic which shows the recessed part of 3rd Embodiment. Schematic which shows the recessed part of 4th Embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail. In the present application, the structures refer to pressure generating elements 21 (FIG. 1), discharge ports 31 (FIG. 1), and communication ports 5 (FIG. 7), which will be described later. Further, in the present application, the substrate on which the above structure is formed is referred to as a first substrate, and the substrate bonded to the first substrate with an adhesive is referred to as a second substrate. That is, the pressure generating substrate 2, which will be described later in detail, may be regarded as the first substrate, and the flow path substrate 1 may be regarded as the second substrate. The generator substrate 2 may also be considered the second substrate.

(First embodiment)
(liquid ejection head)
FIG. 1A is a schematic perspective view of the liquid ejection head 4 according to this embodiment. FIG. 1(b) is a cross-sectional view taken along line AA' shown in FIG. 1(a). As shown in FIG. 1, the liquid ejection head 4 is mainly composed of a flow path substrate 1, a pressure generating substrate 2, and an ejection port substrate 3, and each substrate is bonded with an adhesive 40 (FIG. 2). be.

The channel substrate 1 is formed of a substrate such as silicon, ceramic, or resin. A through hole is formed in the channel substrate 1 by dry etching, wet etching, physical processing, or the like, and this through hole serves as a supply channel 11 for supplying liquid onto the pressure generating element. Furthermore, the channel substrate 1 is formed with a space (pressure generating chamber 12 ) in which a pressure generating element 21 for generating pressure for discharging liquid from the discharge port 31 is provided. When the pressure generating element 21 is a piezo element, the space allows the piezo element to be displaced, and the liquid is ejected from the ejection port 31 by the pressure generated by the displacement of the piezo element.

The pressure generating substrate 2 is formed of a substrate such as silicon, ceramic, or resin. The pressure generating substrate 2 is formed with pressure generating elements 21, electrodes connected to the pressure generating elements 21, circuits (not shown) for selectively supplying power to specific electrodes, and the like. For the pressure generating element 21, a polycrystalline ceramic such as lead zirconate titanate (PZT) imparted with piezoelectricity, a resistance heating element made of an inorganic thin film, or the like is used. Further, a liquid chamber 22 communicating with the supply channel 11 of the channel substrate 1 and adjacent to the pressure generating element 21 is formed.

The ejection port substrate 3 is formed of a substrate such as silicon, ceramic, or resin. Further, the ejection port substrate 3 is formed with ejection ports 31 for ejecting liquid. The ejection port 31 communicates with the liquid chamber 22 , and the pressure generated by the pressure generating element 21 is transmitted to the liquid chamber 22 to eject the liquid from the ejection port 31 .

Epoxy resins, organic silicon materials, metal pastes, and the like are used singly or in combination as adhesives for bonding substrates, and materials are selected in consideration of adhesive strength, liquid contact durability, and the like. These adhesives are applied to the joint surfaces of the substrates, and the substrates are chemically or physically joined together by applying energy such as heat or press.

When a plurality of substrates are bonded to form a liquid ejection head, the order of bonding the substrates and the surfaces to which the adhesive is applied are arbitrary, and the lamination relationship of the three substrates may be appropriate. In other words, the pressure generating substrate 2 is sandwiched between the flow path substrate 1 and the discharge port substrate 3 and joined together.

(bonding of substrates)
The process of bonding each substrate will be described with reference to FIGS. 2 and 3. FIG. FIG. 2(a) is a schematic diagram showing a state in which an adhesive is applied to the surface of the flow path substrate 1 on the side of the pressure generating substrate 2. FIG. FIG. 2(b) is a schematic view of the state shown in FIG. 2(a) when the channel substrate 1 and the pressure generating substrate 2 are joined together. FIG.2(c) is an enlarged view in the area|region B shown in FIG.2(b). FIG. 3(a) is a schematic diagram showing a state in which the flow path substrate 1 and the pressure generation substrate 2 are bonded together, and an adhesive is applied to the surface of the pressure generation substrate 2 on the ejection port substrate 3 side. FIG. 3(b) is a schematic view of the state shown in FIG. 3(a) when the ejection port substrate 3 is joined to the pressure generating substrate 2. As shown in FIG. FIG.3(c) is an enlarged view in the area|region C shown in FIG.3(b).

As shown in FIG. 2A, an adhesive 40 is applied to a surface (bonding surface) 24 of the flow path substrate 1 on the side of the pressure generating substrate 2 that is to be bonded to the pressure generating substrate 2 . Further, in the pressure-generating substrate 2 , recesses 23 are formed in advance on a non-bonding surface 29 that is a surface that is not bonded to the flow path substrate 1 . Next, the channel substrate 1 and the pressure generating substrate 2 are hot-pressed and joined together (FIG. 2(b)). The substrate interface after bonding, that is, the thickness of the adhesive on the bonding surface 24 is typically several μm or less, although it depends on the bonding conditions. , wets and spreads on the pressure-generating substrate. Here, the joint end portion 25 is the end portion of the joint surface 24 on the side of the structure. A pressure-generating element 21 (also referred to as a structure) is present on the pressure-generating substrate beyond the joint end 25 . A recess 23 is formed on the pressure generating substrate 2 between the joint end 25 and the pressure generating element 21 . The surface tension of the adhesive acts on the edge 26 on the joint end side of the concave portion 23, and an action is performed to prevent the excess adhesive 41 that protrudes from moving ahead. As a result, excess adhesive 41 can be prevented from coming into contact with pressure generating element 21 . As a result, it is possible to suppress the influence on the recording quality due to the adhesive protruding from the joint end portion 25 adhering to the pressure generating element 21 . In FIG. 2, the pressure generating substrate 2 corresponds to the first substrate, and the channel substrate 1 corresponds to the second substrate.

Next, as shown in FIG. 3(a), the ejection port substrate 3 with the concave portions 23 bonded in advance is prepared. An adhesive 40 is applied to the surface of the pressure generating substrate 2 on the ejection port substrate 3 side. At this time, recesses 23 are previously formed in the ejection port substrate 3 beside the ejection ports 31 . After that, the liquid ejection head 4 is formed by bonding the ejection port substrate 3 . As in FIG. 2, if excess adhesive 41 protrudes from the joint end 25 and wets and spreads on the ejection port substrate, the adhesive 41 may adhere to the ejection port 31 (also referred to as a structure). Therefore, as described above, by forming the concave portion 23 in the discharge port substrate 3, the surface tension of the adhesive acts on the stepped portion of the concave portion 23, and it is possible to suppress the overflowing adhesive from flowing beyond it. can. As a result, it is possible to prevent the discharge port 31 from being clogged with excess adhesive 41, so that the influence on the print quality can be suppressed. In addition, as an effect of restricting the movement of the protrusion to the vicinity of the ejection port, the volume change of the liquid chamber in the vicinity of the ejection port 31 is suppressed, and there is also an effect of reducing the influence on the ejection amount characteristics. In FIG. 3, the discharge port substrate 3 corresponds to the first substrate, and the pressure generating substrate 2 corresponds to the second substrate.

In addition, if the protruding adhesive exceeds the stepped portion of the recess, the adhesive is accommodated in the recess. This also has the effect of suppressing adhesion of the adhesive to the structure.

(Second embodiment)
A second embodiment will be described with reference to FIG. In addition, the same code|symbol is attached|subjected about the same location as 1st Embodiment, and description is abbreviate|omitted. This embodiment is characterized by the shape of the recess for suppressing the flow of the adhesive. Although the following description will be made using the concave portion 23 formed in the pressure generating substrate 2, the same can be applied to the concave portion formed in the discharge port substrate 3 as well. FIG. 4(a) is a schematic diagram showing the channel substrate 1 and the pressure generating substrate 2 in this embodiment. FIG.4(b) is an enlarged view in the area|region D shown to Fig.4 (a). In the following description, the forming angle .theta. of the recess 23 is the angle formed between the side wall 6 of the recess 23 and the main surface 7 of the substrate, that is, the angle .theta. shown in FIG. 4(b).

As shown in FIG. 4(b), it is preferable that the formation angle θ of the concave portion 23 is less than 90 degrees. When a large amount of adhesive protrudes, the adhesive protrudes due to surface tension at the edge 26 of the recess 23, and when this contacts the inner wall of the recess 23, the damming effect is lost and the adhesive flows into the recess 23. The smaller the formation angle θ of the concave portion 23, the less likely it is that the protrusion will come into contact with the inner wall, and the more likely the damming effect will be maintained. More preferably, the formation angle θ of the concave portion 23 is 70 degrees or less, and more preferably 50 degrees or less. However, if the formation angle θ of the recess 23 is too small, the formation of the recess becomes complicated, so the formation angle θ of the recess 23 is preferably 30 degrees or more.

(Third Embodiment)
A third embodiment will be described with reference to FIGS. 5, 6 and 7. FIG. In addition, the same code|symbol is attached|subjected about the same location as 1st Embodiment, and description is abbreviate|omitted. This embodiment is characterized by the position where the recess 23 is formed and the dimensions of the recess 23 . FIG. 5(a) is a schematic diagram showing the channel substrate 1 and the pressure generating substrate 2 in this embodiment. FIG. 5(b) is an enlarged view of the region E shown in FIG. 5(a).

It is preferable to form the recess 23 at a position as far away from the pressure generating element 21 as possible. When the pressure generating element 21 is a PZT (piezo element), the vibration stress caused by the PZT is likely to be applied to the concave portion 23 dug into the groove, so that the resonance frequency changes. This is because they may be more susceptible. As shown in FIG. 5, the recessed portion 23 is positioned closer to the joint end 25 than an intermediate position 27 between the joint end 25 and the end 33 of the pressure generating element 21 on the joint end 25 side. The effect can be reduced by arranging it so that it fits within the More preferably, when the region between the joint end portion 25 and the end portion 33 of the pressure generating element 21 is divided into three equal parts, the It is preferable to form a recess 23 in the .

For the same reason, it is preferable that the width 28 of the recess 23 is set to a width 30 or less, which is less than half the distance between the joint end 25 and the pressure generating element 21, to reduce the effect on device characteristics. By reducing the width 28 of the recess 23, the reduction in strength around the recess 23 can be minimized. The width 28 of the recess 23 means the length of the short side of the long side and short side of the recess 23 (see FIG. 8).

FIG. 6A shows an example of the concave portion 23 formed in the ejection port substrate 3. As shown in FIG. FIG. 6(b) shows an enlarged view of the region F shown in FIG. 6(a). The depth of the concave portion 23 is preferably as deep as possible, considering the case where the swelling caused by the surface tension of the adhesive collapses and the adhesive spreads inside the concave portion. On the other hand, considering the mechanical strength around the recess and the influence on the device characteristics described above, the shallower the depth, the better. In consideration of these, the depth 36 of the recess 23 (the depth from the bonding surface 24) should be 0.01 times or more and 0.80 times or less with respect to the thickness 35 of the substrate forming the recess. preferable. Furthermore, the depth 36 of the recess 23 is more preferably 0.01 times or more and 0.50 times or less from the viewpoint of mechanical strength around the recess.

FIG. 7A shows an example in which a recess 23 is formed between the supply channel 11 and the joint surface 24. As shown in FIG. FIG. 7(b) shows an enlarged view of the region G shown in FIG. 7(a). As shown in FIG. 7, when the supply channel 11 and the liquid chamber 22 are communicated with each other through a communication port 5 (also referred to as a structure) having a diameter smaller than that of the supply channel 11, excess adhesive Even if the amount of the liquid 41 is small, if the communication port 5 is partially blocked, the flow resistance of the liquid will increase, which is not preferable. Therefore, in this embodiment, as shown in FIG. By forming such a concave portion 23 , it is possible to prevent excess adhesive 41 from blocking the communication port 5 .

(Fourth embodiment)
A fourth embodiment will be described with reference to FIG. In addition, the same code|symbol is attached|subjected about the same location as 1st Embodiment, and description is abbreviate|omitted. This embodiment is characterized by the region where the concave portion 23 is formed. FIG. 8(a) is a plan view of the flow path substrate 1 and the pressure generating substrate 2 joined together as viewed from the pressure generating substrate side. 8(b) to (d) are enlarged views of region H shown in FIG. 8(a). As an example, FIG. 8 shows a form in which the recess 23 is formed between the pressure generating element 21 and the joint end 25, but the present embodiment is not limited to this. That is, as shown in FIG. 3(c), the same applies to the case where the recess 23 is formed between the ejection port 31 and the joint end 25. As shown in FIG.

As shown in FIGS. 8(b) to 8(d), the concave portion 23 may be arranged in any plane as long as it is located between the joint end portion 25 and the pressure generating element 21. FIG. Therefore, as shown in FIG. 8(b), the concave portion 23 may be formed continuously so as to surround the pressure generating element 21, or may be formed intermittently as shown in FIG. 8(c). You may Alternatively, as shown in FIG. 8D, a plurality of recesses 23 may be formed so as to surround the pressure generating element 21 .

A liquid ejection head 4 was manufactured by bonding the flow path substrate 1, the pressure generation substrate 2, and the ejection port substrate 3. FIG. The flow path substrate 1 includes a supply flow path 11 having an opening size of 100 μm×100 μm and a pressure generation chamber 12 having a size of 150 μm×2000 μm and a depth of 100 μm in a silicon substrate having a thickness of 500 μm. As the pressure generating substrate 2, a PZT element made of lead zirconate titanate was formed on a silicon substrate with a size of 100 μm×1900 μm together with electrodes and a driving circuit. In the pressure generating substrate 2, a liquid chamber 22 having a size of 150 μm×2500 μm and a depth of 100 μm was formed, and a concave portion having a width of 10 μm was formed so as to surround the PZT element. In the ejection port substrate 3, ejection ports 31 having a diameter of 20 μm were formed in silicon having a thickness of 10 μm. These three substrates were bonded with a thermosetting adhesive mainly composed of silicon-containing benzocyclobutene resin. Observation of the ejection port 31 of the liquid ejection head did not confirm clogging due to excess adhesive overflowing.

For comparison, when a liquid ejection head was manufactured in which the recesses 23 were not formed in the pressure generating substrate 2 and the ejection port substrate 3 and the other structures were manufactured with the same dimensions, the clogging of the ejection ports 31 due to the protrusion of the adhesive was 0.00. It occurred at a rate of 5%.

2, 3 first substrate 2, 3 second substrate 4 liquid ejection head 23 concave portion 24 bonding surface 29 non-bonding surface 25 bonding end portion 40 adhesive

Claims (16)

a first substrate comprising a structure;
a second substrate bonded to the first substrate via an adhesive;
In a liquid ejection head having
The first substrate is formed with a bonding surface that is bonded to the second substrate via the adhesive and a non-bonding surface that is not bonded to the second substrate,
The liquid ejecting method according to claim 1, wherein a concave portion is formed in a region of the non-bonding surface between the structure and a bonding end, which is an end of the bonding surface on the side of the structure. head. The liquid ejection head includes an ejection port substrate having ejection ports for ejecting liquid, a pressure generation substrate having pressure generation elements for generating pressure for ejecting the liquid from the ejection ports, and liquid on the pressure generation elements. and a channel substrate comprising a channel for supplying
The first substrate is the pressure generating substrate,
The second substrate is the channel substrate,
2. A liquid ejection head according to claim 1, wherein said structure is said pressure generating element. The liquid ejection head includes an ejection port substrate having ejection ports for ejecting liquid, a pressure generation substrate having pressure generation elements for generating pressure for ejecting the liquid from the ejection ports, and liquid on the pressure generation elements. and a channel substrate comprising a channel for supplying
the first substrate is the ejection port substrate;
The second substrate is the pressure generating substrate,
2. A liquid ejection head according to claim 1, wherein said structure is said ejection port. The liquid ejection head includes an ejection port substrate having ejection ports for ejecting liquid, a pressure generation substrate having pressure generation elements for generating pressure for ejecting the liquid from the ejection ports, and liquid on the pressure generation elements. and a channel substrate comprising a channel for supplying
The pressure generating substrate is formed with a communication port having a diameter smaller than the flow path diameter of the flow path,
the channel of the channel substrate is connected to the communication port of the pressure generating substrate,
The first substrate is the pressure generating substrate,
The second substrate is the channel substrate,
2. The liquid ejection head according to claim 1, wherein the structure is the communication port. 5. The liquid ejection head according to any one of claims 1 to 4, wherein the formation angle of said recess is less than 90 degrees. 6. The liquid ejection head according to any one of claims 1 to 5, wherein the recess is formed at an angle of 70 degrees or less. 7. The liquid ejection head according to any one of claims 1 to 6, wherein the recess is formed at an angle of 50 degrees or less. 8. The liquid ejection head according to any one of claims 1 to 7, wherein the recess is formed at an angle of 30 degrees or more. 9. The recess according to any one of claims 1 to 8, wherein the recess is formed so as to be located closer to the joint end than an intermediate position between the joint end and an end of the structure on the joint end side. A liquid ejection head as described. When the region between the joint end and the end of the structure on the joint end side is divided into three equal parts, the recess is the region closest to the joint end among the three equal parts. 10. The liquid ejection head according to any one of claims 1 to 9, wherein the liquid ejection head is formed so as to be contained within. 11. The liquid ejection head according to any one of claims 1 to 10, wherein the width of the recess is half or less of the distance between the joint end and the structure. 12. The depth of the recess from the bonding surface is 0.01 times or more and 0.80 times or less the thickness of the first substrate in which the recess is formed. 2. The liquid ejection head according to item 1 or 2. 13. The depth of the recess from the bonding surface is 0.01 times or more and 0.50 times or less the thickness of the first substrate in which the recess is formed. 2. The liquid ejection head according to item 1 or 2. 14. The method according to any one of claims 1 to 13, wherein when the plan view of the first substrate and the second substrate is viewed, the recess is formed so as to continuously surround the periphery of the structure. A liquid ejection head as described. 14. The method according to any one of claims 1 to 13, wherein when the plan views of the first substrate and the second substrate are viewed, the recess is formed so as to intermittently surround the structure. A liquid ejection head as described. 16. The structure according to any one of claims 1 to 15, wherein a plurality of said recesses are formed surrounding said structures when viewed from plan views of said first substrate and said second substrate. liquid ejection head.

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